Spark plug



J. DEVINE SPARK PLUG Nov. 9, 1937.

Filed Feb. 25, 1937 U Ma Rm m m N R W m m A 0 MY J I Patented Nov. 9, 1937 ,UNITED STATES PATENT OFFICE sraax PLUG Julius Devine, New York, my.

Application February 25, 1937, Serial No. 121,610

Claims. ((31. 123-169) This invention relates to spark plugs and parsurround the lower portion of electrode l8, and inticularly to spark plugs of the type capable of sulating sleeves ll adjacent to the head it, said producing proper ignition in internal combustion washers preferably being of increasing outer diengines of the relatively high compression class. ameter away from said head i. i

5 An object of the invention is to provide a new The construction of the head I! is as follows: 5 and improved spark plug of relatively great dura- Around the spindle I 5, there is provided a groove bility by reason of the incorporation therein of a 20 with an upstanding rim 2|. 'When the insulanovel combination and interrelation of parts protion I8 is placed around the spindle it is producing a unit which is capable of withstanding the jeoted into the groove 2|. The space between the 10 highest temperatures and compressions eninsulation l8, and the rim 2| is occupied by a filler 10 countered under the most trying operating con- 22, to be described hereafter but whose function ditions. 1 I is to keep the bottom of the insulation I8, gas

Another object of the invention is to provide tight, that is, to prevent any gas entering between in a spark plug of-the type in;which one of the the insulation i8, and the spindle i5.

ll electrodes is in the form of a centrally disposed The filler 21 may 'beany one of a number of pin, or spindle, novel -means for insuring "a gas articles that can be used, such as solder,-cem'ent, tight joint around said spindle. or a soft metal asa brass wedge 23, may'beforced' These and other objects ofthe invention will in and hammered in till it fills the groove 20. be apparent to those skilled in the art from the The outside of the rim may be forced inwards by following description, taken in connection: with pressure so as to completely flll the groove.

the accompanying drawing wherein'are illustrated On top of the insulating washers 19, there is two embodiments of the invention. It is to be seated a gland 21, externally threaded as at 28, expressly understood, however, that the drawing for engagement with the screw threaded poris for the purpose of illustration only and is not tion 12, and surrounding the intermediate portion designed as a. definition of the limits of the inof electrode i5, and insulating sleeves II. The 25 vention, reference being had for this purpose to gland TI, is provided with an inclined bottom the appended claims. portion 30, the surface of which conforms in slope Referring to the drawing: to shoulder ll, of the shell at.

Fig. i represents a spark plug in longitudinal The gland 21, is made of steel just soft enough central section. so that the center of which may he worked, that Fig. 2 a view taken on 2-4 of Fig. i, is the gland 2!, has a portion removed from its Fig. 3 is a section of the filler. top forming a circular triangular void ii, a thin Fig. 4 is a view or the grooved head of spindle. wall 32 is left adjacent the spindle l5 and insula- Fig. 5 is a section of a modified form of spark tion ii. If desired a similar portion may be re- 35 plug. moved from the bottom of the gland I! forming Fig. 6 shows the steel collar and brass wedge. a circular triangular void 33, with acorresponding Fig. 7 shows the steel wedges. thin wall 38.

Referring now to the drawing wherein like Hard steel wedges 3i and 31 somewhat larger reference characters indicate like parts through- .than the voids 3|, and II, are adapted to be out the several views. In the form shown, the forced into the voids thereby forcing the soft plug comprises a shell iii, exteriorly threaded as steel walls 32, and 35, tightly against the insuat it for threaded engagement with an opening lation i8, and thereby providing a gas tight seal in a cylinder wall of an internal combustion enaround the electrode l5. Either one or two gine in the usual manner. The upper part of the wedges may be used.

Shell ill, is internally threaded as at 12 and is of The shell ill is provided with an inclined elec- 5 larger diameter than the lower part so as to protrode 38 projecting into the proper spaced rela-' vide an inner shoulder i3. tionship to the center electrode i5, and spark A gasket i4 is placed on the shoulder i3. point ll. The positive electrode comprises a metallic A plurality of other insulating washers 38 are so p e having at its lower end an enlarged provided resting on a washer 40, which is superhead i6, which car s a park p point H. An imposed on the gland 21 and surrounding subinsulator 88, preferably mica sleeves surrounds stantially the remaining upper portion of eleceiect P ly throughout its length, trode i5, and insulating sleeves I I, said washers resting at its lower end on the bead ii. A plupreferably decreasing in diameter towardthe g5 rality of insulating washers l8,preferably of mica, top of electrode ii. 56

A resilient cap ill of brass and a washer 62 of asbestos being inserted between the outer end of the mass of mica washers 39, and the terminal nut 33, which is in threaded relation with the upper end id of the electrode to.

A binding post 35 is provided to tighten wires (not shown) to the plug.

In Fig. 5 there is illustrated another embodiment of the present invention. In this form the gland it has its inner center cut with two opposing inclinations 4lldt coming to an apex towards the middle of the gland. Wedge rings 36, 31 are placed within the inclinations M, 48 but not touching each other. A soft metal tube 49, is placed against the insulating material it; right behind the wedge rings 36, 31 so that when the wedge rings are taken up or forced against each other, the soft metal tube 49 will prevent the piercing of the insulating sleeves Hi.

In the modification the spindle head I6 is provided with a shoulder on which the insulation sleeves rest. The seal at this point is made by placing. over the spindle and insulation l8 a steel collar 60 the upper portion of which is flat or uniform thickness and lower portion having an internal outward inclination 5|. A brass wedge ring 52 having an outside inward inclination 53 but longer than the inclination 5! of the steel collar. This brass wedge 52 is placed underneath the steel collar 50 and allowed to project somewhat below the collar 50.

The seal is made tight by forcing the collar 50 downwards and thus squeezing the brass ring 52 against the insulation I8 andspindle l5.

There is thus provided an improved spark plug structure which is rugged and strong both mechanically and electrically and which is compactly and easily assembled from a small number of parts. Due to its simplicity, it is also cheap to manufacture. Novel means are pro vided in this spark plug for effectively preventing the escape of gases from the engine cylinder, through the spark plug structure, and thus decreasing the loss of compression, as well as prolonging the life of the plug.

It will be obvious that the invention is not limited to the specific forms described and illus- QWQQQWI trated in the drawing but is capable of a variety of mechanical embodiments. Various changes, which will now appear to those skilled in the art, may be made in the form, details of construction, and arrangements of parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What I claim is:

i. In a spark plug, a gland, a spindle, insulation between said spindle and said gland, said gland having a portion removed therefrom leaving a thin sleeve against the insulation, a wedge ring adapted to be forced into the removed portion and forcing the sleeve against the insulation.

2. In a spark plug, a gland, a spindle, insulation surrounding said spindle, a sleeve of soft metal against the insulation and a. pair of separated opposite acting wedges acting on the gland to forcethe soft metal sleeve against the insulation.

3. In a spark plug, a spindle, insulation surrounding said spindle, a gland surrounding said insulation and comprising inner and outer portions connected together at approximately the center thereof and means for forcing the inner portions against the insulation.

4. In a spark plug, a spindle having an enlarged head and a groove formed within said head around the spindle, an insulation sleeve surrounding said spindle and projecting Within said groove, a filler adapted to firmly seal the portion between the insulation sleeve and the outer face of the groove, said filler comprising a brass conical ring which is forced to fill the said portion.

5. In a spark plug, a gland, a spindle, insulation between said spindle and said gland, a soft metal sleeve surrounding said insulation, said gland. being out on its inside with two opposing wedge surfaces coming to an apex at about half way its height, two opposing steel wedge rings adapted to be forced into the space between the wedge surfaces and the soft metal sleeve for tightening the sleeve around the insulation.

JULIUS DEVINE. 

